1. Field of the Invention
This invention relates to alkoxy or arylmethoxy ethanes. This invention particularly concerns a process for preparation of such compounds. More particularly, the invention teaches a novel process for preparation of 2-alkoxy (or 2-arylmethoxy)-1-aroxyethanes, a class of compounds useful in a variety of diverse applications such as improved sensitizers or modifiers for thermal sensitive papers and as dispersants, emollients, and texture enhancing agents in cosmetics and lotions.
2. Description of Related Art
There are several methods described in the literature for preparing 1-benzyloxy-2-phenoxyethane represented by the structure A: ##STR4##
C. Berggardh [Finska Kemistsamf.Medd., 42, 76 (1933)] and E. M. Van Duzee and H. Atkins [J. Amer. Chem. Soc., 57, 147 (1935)] prepared (A) by reacting sodium 2-phenoxyethoxide with benzyl chloride. Also, C. L. Butler and A. G. Renfrew [J. Amer. Chem. Soc., 60, 1582 (1938)] and C. L. Butler and L. H. Cretcher [U.S. Pat. No. 2,172,606 (1939)] obtained (A) by treating 2-benzyloxyethyl p-toluenesulfonate with potassium phenoxide. These two methods require the preparation of one or both starting materials in a separate step and involves the use of either potassium or sodium metal that are expensive and difficult to handle in scale up operations. J. S. Bradshaw, B. A. Jones and J. S. Gebhard [J. Org. Chem., 48, 1127 (1983)] made (A) by reductive desulfurization of 2-phenoxyethyl thiobenzoate using Raney nickel. Again, the starting material thiobenzoate, prepared from not readily available 2-phenoxyethyl benzoate by thionation, makes this process not amenable to scale up. A. Goto [U.S. Pat. No. 5,179,068] described a method for preparing 1,4-bis (2-aroxyethoxymethyl) benzenes by reacting 2-phenoxyethanol with p-xylylene dichloride and aqueous sodium hydroxide using trioctylmethylammonium chloride as catalyst in toluene. Goto also, described a process for making 1,4-bis (2-aroxyethoxymethyl) benzenes in two steps starting from substituted phenol and ethylene carbonate. In the first step, the substituted phenol and ethylene carbonate were heated with catalytic amounts of potassium carbonate in chlorobenzene to generate the corresponding substituted phenoxyethanol. In the second step, the substituted phenoxyethanol was reacted with p-xylylene chloride and aqueous sodium hydroxide using trioctylmethylammonium chloride as catalyst in chlorobenzene. The success of this tandem two step process depends on the complete conversation of the substituted phenol to the corresponding substituted phenoxyethanol in the first step; otherwise, a mixture of inseparable products are formed, resulting in low yield of the desired product.